A Napier shop is giving out free lollies with sales of a controversial party drug.

Worried parents claim local teenagers are becoming addicted to the legal drug K2, with one teen threatening suicide if she did not get it.

Maraenui mother Minnie Ratima said her daughter and her friends become angry and anxious after taking the drug, while another young woman went into anaphylactic shock.

K2 caused concern in the lower South Island last year after its use was tied to paranoia, psychosis, vomiting and a racing heart rate.

Associate Health Minister Peter Dunne banned a substance found in K2 products, known as EAM-2201, in December. A modified version is now being sold.

Hawke's Bay District Health Board mental health and addictions spokesman Jason Exton was seeing more young people with symptoms from smoking K2 and other synthetic cannabinoids.

Because of the unknown properties in the drugs, he said the side-effects were unpredictable, and often more severe than smoking cannabis. The psychosis could last days, he said.

The Maraenui dairy is giving away a lolly mixture with each pack of K2 bought for $20.

The owner, who would not be named, said it was so children did not know he was selling drugs. He saw no problem with selling the drug, saying it was better than alcohol.

"In most cases most people take it to relax. Every kind of people buy it - even kind old ladies, and gentlemen."

He insisted he sold it only to people over 18, and kept it hidden behind the counter.

Community group Tu Tangata Maraenui said it had asked him to stop selling the drug, but he ordered them out of the shop.

Under smokefree legislation, K2 or any product that is smoked cannot be sold to those under 18.

Outside the store, a group of local K2 users approached The Dominion Post worried that their supply was under threat. They said they smoked it every day, saying it was a "better buzz" than cannabis and it "kept them going".

However, they said some of the younger users couldn't handle it and walked around like zombies. When asked if it made them aggressive, they replied: "Yeah, when you got none."

New Zealand Drug Foundation executive director Ross Bell was outraged at what he called the "immensely stupid" actions of the dairy owner.

"This guy thinks he is disguising the sale by providing sweets, but instead he's connecting a potentially risky substance with lollies."

Regulations on selling legal highs are expected to tighten this year. Mr Dunne is pushing for a new regime to become law by the middle of the year.

At present, manufacturers are not required to list the ingredients of products. The new law reverses the onus of proof, so manufacturers will have to be prove their products are safe.

Mr Dunne said the Maraenui dairy had better be certain it was not selling an illegal product. "And as for selling such products with lollies, clearly it is deeply unethical, but it is not illegal."

WHAT IS K2?

A synthetic cannabinoid which mimics the effect of THC, one of the ingredients in cannabis.